The present invention relates to an article of furniture, and more particularly, to compression joints connecting structural members in furniture.
Many articles of furniture include a vertical support assembly in which one or more horizontal elongated members is secured. One example of such an article is a metal support structure for a table, wherein each of the vertical assemblies is a table leg and the elongated members are rails and stretchers interconnecting the table legs. The rails extend between upper portions of the table legs, while the stretchers extend between the lower portions of the table legs to provide the support structure with the desired strength.
Typically, in prior table support structures, the rails and stretchers are welded, or brazed, to the legs. However, this construction is relatively expensive due to the fact that welding and brazing are labor intensive. Further, the welding operation sometimes damages the prefinished metal parts so that the parts are spoiled. Finishing, such as polishing, must also be performed to properly finish the welds and brazes.
Although expandable joints for connecting horizontal members to vertical assemblies are available, these connections are not without their drawbacks. One such connection includes rail ends positioned between caps which are threaded onto a common rod to secure the rail end between the caps. The rail ends include angled notches and the caps include facing frusto-conical surfaces engaging the notches to further aid in securing the rail within the assembly. Further, the rail end defines a vertical groove which interfits with a rib extending from a sleeve positioned between the two caps to prevent the rail from twisting with respect to the assembly. See U.S. Pat. No. 3,986,316, entitled "JOINT ASSEMBLY" and issued Oct. 19, 1976, to Blodee. Proper tightening of such an assembly is difficult due to the facts that (1) the caps rotate against the rails restricting movement of the caps and (2) great care must be taken in gripping the caps to insure that the finish is not spoiled. Second, interfitting the vertical groove on the rail end with the relatively low rib on the sleeve is difficult further complicating assembly. Third, the completed assembly appears unfinished because various ribs are left exposed and because the diameter of the leg varies greatly from top to bottom.
Another assembly includes a slotted holding bolt with which the rail ends slidingly and tightly interfit. Grooves transverse to the rail are machined into opposite sides of the rail end which interfit with the holding bolt to prevent the rails from moving radially with respect to the bolt. Caps are provided on the bolt to engage opposite sides of the rail to further secure the rails. See U.S. Pat. No. 3,670,899, entitled "RAIL CONNECTION" and issued June 20, 1972, to Kronenberg et al. However, proper tightening of the caps is difficult because (1) care must be taken in gripping the caps to avoid marring their finish and (2) the caps rotate against the rails restricting movement of the caps. Further, the holding bolt and grooved rails are machined resulting in relatively high product cost.
Yet another joint includes a rail, a tie-rod extending through the rail end, and caps and a sleeve to hide the tie-rod and rail end. See U.S. Pat. No. 2,477,997, entitled "TUBULAR JOINT" and issued Aug. 2, 1949, to McArthur. However, the rail is connected to the tie-rod primarily due to the fact that the tie-rod extends through the horizontal member which by necessity has substantial horizontal width in order to provide the opening through which the tie-rod extends. Accordingly, the McArthur construction is not adaptable to assemblies where the rails are relatively thin and not hollow.